Chlorinated aromatic dielectric with scavenger



Aug. 28, 1951 E. E. HARDY CHLORINA'IED AROMATIO DIELECTRIC WITHSCAVENGER FIG.I

FIG. 3

Filed Dec. 28. 1948 DIELECTRIC commune HALOGENATED AROMATIC ELECTRODESCOMPOUND AND AMINATED- N- PHOSPHORYL-O- AMINO BIPHENYL AS CORROSIONINHIBITOR )FIG. 4

FIG. 5

METAL FOIL PAPER IMPREGNATED WITH HALOGENATED AROMATIC COMPOUND ANDCORROSION INHIBITOR Edur E. Hardy I INVENTOR.

BY MG ATTORNEY Patented Aug. 28, 1951 UNITED STATES PATENT OFFICE 7CHLORINATED AROMAfIj I C DIELECTRIC WITH SCAVENGER Edgar E. Hardy;Amnston, 51s,, asgiglidr" to Man santo Chemical Company,- St. Louis,Mo., a corpartition of Delaware Application nc'titer 28, 1948; SerialNo. 67,662 13 Glaims. (01. 252- 66) above; compositions.

Halogenated organic compounds,- more particularly halogenated aromaticcompounds such as chlorinated biphenyl' and chlorinated naphthalene arehighly useful electrical insulating materials because of their highdielectric constants, thermal stability, resistance to oxidation,-non-flammability and other" valuable properties. Howeveri it hasbeenfound that when e15 posed to elevated temperatures and/or high voltages;they partially decompose liberating hydrogen' halides which have anexceedingly deleterious action on the paper insulation and metal partsof electrical-apparatus.-

For example in transformers; circuit breakers and-other electricaldevices in which arcing o ecars, the development of hydrogen halidesas-a result of" the above decomposition presents a serious problem asthey decrease the dielectric strength of the composition containingsame'and cause considerable damage by attacking paper insulation andcorroding metal parts of the pai'atus inwhich the compositionis used;Tjhe undesirable eflect of the above"decomposition is further manifestedwhen the above halogenated organic compounds are used as capacitoriinpregnants: Thus, under high operating tempera tures and directcurrent voltages; capacitors' im pregn'ated therewith undergo acharacteristic type-'of deterioration which results in an ever-increasing leakage current, a short capacitor "hie; visible" localizeddecomposition of V the dielectric and corrosion of the electrodes.Moreover, i'n' -the case 'of capacitors operating onalternatingcurrent-the decomposition sometimes results in an excessiveincrease in powrfactor of the dielectric material.

It is; therefore, the objectof the presentinven tion to provide newcompositions of'matter-contal'n'ing halogenated organic compoundswherein the above" objectionable properties are either completelyeliminated or substantially reduced.

An-additional object is to provide transformers, capacitors,circuitbreakers, cablesand thelike containing halogenated organiccompoundsin combination with a corrosion inhibitor or-scavedger wherebythe deleterious action of hydrogen halides on thepaper insulation andmetal parts thereof is eliminated or materially reduced.

Another object is to provide a capacitor impregnant containinghalogenated organic compounds and al' corrosion inhibitor or scavenger,whereby the deleterious effect of hydrogen halides on the electrodes andpaper insulation of capacitors is substantially reduced or completelyelirninated with the result that the capacitor has a longer useful lifeand greaterdielectric stability than similar capacitors not containingthe corrosioninhibitor.

A further object s to pr I vide the ,c'ellulosic sulation intransformers containing: litiuidhalogenated organic compounds withprotection against rapid destruction by hyd rQgen halides eyelved as theresult of a minor are within the tran fq m i s, permitting o i reeeiififthe assembly by rapid replacement or removalof the entire paperinsulation of thetransformer with'a ponsequent high cost of repair. v J

A still further object is to provide switches, cables and the likecontaininghalogenated organic comppunds and a corrosion inhibitor orseavenger which practically eliminates the rusting and corrosionnormally accompanying V the useof such devicesfilled with halogenatedorganic compounds per se. A Other objects and advantages of the presentinvention willbecome apparent 'to those skilled in the art as thedescription proceeds. I l have discovered that halogen decompositionpro'du'ctscan be rendered substantially innocuous ahd the aboveobjectives accomplished if; in accbrdan'cewith the present inventions,the hategenated organic materials to be protected are associated with arelatively small ameunt of aminated-N phosphoryl-o aminobiphenyl,"whichcompound has the following chemical'formula:

The above compound possesses the surprising property of inhibiting thedeleterious action of hydrogen halides on metals and organic insulationmaterials'without materially affecting the electric'ahproperties of thehalogenated compound or composition with which it is incorpora-ted:

For 'amore complete .understanding ofthe pres- 3 ant invention,reference is made to the accompanying drawings and the experimental datahereinafter presented in the specific examples.

Figure l is a front elevation partly in section of a transformer; Figure2 illustrates a switch in a similar manner; Figure 3 represents a rolledcapacitor; Figure 4 shows a sectional view of a portion of theelectrodes and dielectric sheets of Figure 3; and Figure 5 is a sideview of a cable, the casing being partly removed to permit the interiorof the parts to be seen.

The transformer illustrated in Figure 1 comprises a casing 1, core 2,coils 3 insulated with manila paper, kraft paper, cotton or otherfibrous insulation, insulating and cooling medium 4, lead-in bushings 5,and suitable leads 6 connected to the coil assembly. The insulating andcooling medium may consist of chlorinated biphenyl, trichlorbenzene andaminated-N-phosphoryl-oaminobiphenyl in the following proportions.

Parts by Weight Chlorinated biphenyl (60% Cl) 60 Trichlorbenzene 40Aminated-N-phosphorylo-aminobiphenyl 0.1

reduce the corrosion of the metal parts of the transformer which come incontact therewith in the presence or absence of air.

The switch shown in Figure 2 comprises a casing 6, fixed contacts 1 and8, and movable contacts 9 and I0 which cooperate therewith. The movablecontacts are mounted upon a support II which in turn is operativelyconnected to actuating levers l2. The following is illustrative of asuitable arc quenching liquid which may be used in this device, it beingunderstood that the invention is not limited thereto.

Parts by Weight Chlorinated biphenyl (55% Cl) 80 Trichlorbenzene 2OAminated-N-phosphoryl-o-aminobiphenyl 0.05

In the operation of electric switches, the unavoidable arcing whichaccompanies make-andbreak of the switch contacts results in partialdecomposition of the chlorinated biphenyl or other halogenated organiccompounds. The presence of aminated-N-phosphoryl-o-aminobiphenyl in theabove liquid renders the halogen decomposition products innocuous withthe result that switches provided therewith are substantially free fromthe corrosion normally accompanying the use of such devices filled withhalogenated organic compounds per se.

The capacitor hown in Figure 3 is made up of alternate layers of metalfoil such as aluminum or tin foil separated by sheets of dielectricmaterial. It is produced by interleaving two dielectric sheets, such aslinen or kraft paper, with the metal foil, and rolling the interleavedsheets in the conventional manner. The rolled capacitor Composition IPer cent by weight Liquid chlorinated biphenyl, particularly chlorinatedbiphenyl containing from 42% to 60% by weight of chlorine. 0-100Conventional chlorinated organic dielectric materials About -0Aminated-N-phosphoryl-o aminobiphenyl 0.01-1

Composition II Parts by weight Chlorinated biphenyl (42%-60% Cl) 75Trichlorbenzene 25 Aminated-Nphosphoryl-o-aminobiphenyl 0.1

Of the above range of compositions, the preferred capacitor impregnantis one having the following composition:

I Parts by weight Chlorinated biphenyl (55% Cl) 75 Trichlorbenzene 25Aminated-N-phosphoryl-o-aminobiphenyl 0.1

The presence of aminated-N-phosphoryl-oaminobiphenyl in chlorinatedbiphenyl or other halogenated organic compounds provides excellentprotection against the deleterious action of halogen decompositionproducts on metal, paper and other organic insulation material andconsequently capacitors provided therewith will have a longer usefullife and greater dielectric stability than similar capacitors containinghalogenated organic compounds per se. Moreover, capacitors containingthe above compound will not exhibit an ever increasing power factor withtime when operated at high temperatures and voltages as is typical ofcapacitors impregnated with halogenated organic materials which are notassociated with the above corrosion inhibitor.

Figure 4 shows a section of one turn of the finished rolled capacitorillustrating the alternate electrodes and dielectric layers. Inaccordance with the present invention, the finished capacitor contains ahalogenated organic compound, preferably chlorinated biphenyl, and aminor proportion of aminated-N-phosphoryl-o-aminobiphenyl.

The cable of Figure 5 comprises a core 13, cable conductors l4,insulation consisting of paper or other suitable material I5 and acasing H5. The space between the insulated conductors and the casing isfilled with a mixture of aminated-N-phosphoryl-o-aminobiphenyl and anyof the liquid chlorinated organic compounds mentioned above. Such acomposition may consist of a mixture of the following ingredients, butit is to be clearly understood that the invention is not restrictedthereof.

Parts by weight Chlorinated biphenyl (60% Cl) 50 Trichlorbenzene 50Aminated-N-phosphoryl-o-aminobiphenyl about 0.1

'aaearee The experimental data hereinafter presented illustrate in astriking manner the scavenging or corrosion inhibiting action ofaminated-N-phosphoryl-o-aminobiphenyl on dielectric compositionscontaining halogenated organic compounds. In accordance therewith, theefieot of the corrosion inhibitor is brought out by showing andcomparing the action of an HCl-saturated halogenated dielectriccomposition, with and without the inhibitor, on organic dielectricmaterial such as paper. The eiiectivenes's of the inhibitor ismanifested by the protection it affords paper against attack by hydrogenchloride and the degree of attack is indicated by the extent to" whichthe tensile strength of the paper is decreased. This will be renderedmore apparent by refer ence to the following examples.

EXAMPLE 1 Six strips of manila wrapping paper (6" X 1") were humidifiedat 65% R. H. at 70 F. for a period of 48 hours and subjected to tensilestrength tests. These tests were run on a Scott IP2 serigraph with a jawseparation or" 3 inches and a rate of travel of 34.5 seconds for a loadof so lbs. The result of these tests, being the average of 6 breaks, wasas follows:

Tensile strength of paper sample's 46.2 lbs/in.

EXAMPLE 11 Six strips of the same piece ,of manila wrapping paper ('7 x1") were allowed to soak at a temperature of 75 C. for 1 /2 hours in anHCl saturated solution consisting of 60 parts by weight of chlorinatedbiphenyl (60% Cl) and 40 parts by weight of trichlorbenzene and at theend of this operation, the papers were soaked for 15 minutes in benzene,another 15 minutes in methanol and dried. After cutting one half inch-from each end of the dried paper strips, they were subjected to theabove tensile strength tests with the iollowing result:

Tensile strength of impregnated paper samples 11.5 lbs/in.

These examples demonstrate that HCl had a highly deleterious action onthe samples since the tensile strength of the paper changed from 46.2lbs/in. to 11.5 lbs./in., a decrease in tensile strength ofapproximately 75%.

EXAMPLE III The foregoing example was repeated using samples of the samepaper and the same impregnant except that 0.1 part by weight ofaminated-N-phosphoryl-o-aminobiphenyl was added. ihe tensile strength ofthe impregnated paper Was found to be 25.2 lbs./in., thus demonstratingthat the above compound is a highly effective material for renderinghalogen decomposition products such as HCl innocuous to paper or otherfibrous organic dielectrics.

The following table illustrates the electrical properties of thedielectric composition consisting of 60 parts by weight of chlorinatedbiphenyl (60% Cl) and 40 parts by weight of trichlorbenzene and alsoshows the effect thereon of adding 0.1 part by weight ofaminated-N-phosphoryl-oaminobiphenyl.

The above experimental data indicate that aminated-N-phosphoryl-oaminobiphenyl does not seriously affect, but actually improves, theelectrical properties of the halogenated organic compounds associatedtherewith and that, therefore, such compositions are eminently suitablefor use in transformers, capacitors, switches, cables and otherelectrical devices.

The description of the present invention has been directed primarily tocompositions containing chlorinated biphenyl, trichlorbenzene andaminated-phosphoryl-o-aminobiphenyl, but it is to be understood that theinvention is not restricted thereto but embraces halogenated organiccompounds generally. Thus, the above compound may be used as a scavengeror corrosion inhibitor for chlorinated naphthalene, chlorinated diphenylketone, chlorinated diphenylv oxide, chlorinated diphenyl methane,chlorinated diphenyl ethane, chlorinated benzene, chlorinated toluene,chlorinated nitro diphenyl, chlorinated alkylated benzenes, chlorinatedalkylated biphenyls, ethyl trichlorbenzene, ethyl tetrachlorbenzene,ethyl pentachlorbenzene, chlorinated terphenyls, chlorinatedquaterphenyls, chlorinated parafiinic hydrocarbons, chlorinatedalicyclic hydrocarbons, chlorinated oxygen-containing organic compounds,chlorinated rubber, chlorobutadiene polymers, chlorinated fats,chlorinated vegetable oils, chlorinated animal oils, chlorinated mineraloils or mixtures of two or more of these. In place of the chlorinatedcompounds, the corresponding fluorine,

bromine and iodine derivatives may be used. In

fact, any halogenated organic compound or composition which tends byreason if its halogen content to cause corrosion of metals ordehydration of paper or organic fibrous insulation, may be renderedsubstantially innocuous by means ofaminated-N-phosphoryl-o-aminobiphenyl.

The method of incorporating aminated-N- phosphoryl-o-aminobiphenylvaries with the halogenated organic compound or composition. If thecompound or composition is liquid at room temperature, the abovecompound is merely dissolved therein in suitable concentrations; if itis a solid, the aminated-N-phosphoryl-o-aminobiphenyl is blendedtherewith by the use of solvents or swelling agents or by means ofmixing rolls, etc. In the case of halogenated polymers, theaminated-N-phosphoryl-o-aminobiphenyl may be incorporated before, duringor after polymerization of the corresponding monomers.

The quantity of aminated-N-phosphoryl-oaminobiphenyl used varies withthe halogenated organic compound or composition. In general,satisfactory results are obtained by employing this compound in anamount varying from 0.05% to 1% and preferably from 0.05% to 0.1% byweight of the halogenated organic compound or composition, but it is tobe understood that the invention is not limited thereto as slightlylower operations in which this may be done without harmful effects.

As widely different embodiments of this invention may be made withoutdeparting from the spirit thereof, it is to be understood that theinvention is not limited to the specific embodiments except as definedin the appended claims.

I claim:

1. A composition of matter consisting essen tially of a halogenatedaromatic compound and as a scavenger thereforaminated-N-phosphorylo-aminobiphenyl, said scavenger being employed inan amount sufficient to render the halogen decomposition products ofsaid halogenated aromatic compound substantially innocuous.

2. A composition of matter consisting essentially of a chlorinatedaromatic compound and as a scavenger therefor about 0.01% to about 1% byweight of aminated-N-phosphoryl-oaminobiphenyl.

3. A heat transfer and dielectric composition consisting essentially ofchlorinated biphenyl and as a scavenger therefor about 0.05% to about 1%by weight of aminated-N-phosphorylo-aminob-iphenyl.

4. An insulating and cooling medium for electric apparatus consistingessentially of a liquid chlorinated biphenyl and as a scavenger thereforabout 0.05% to about 1% by weight ofaminated-N-phosphoryl-o-aminobiphenyl, said chlorinated biphenylcontaining from 42% to 60% by weight of chlorine.

5. A dielectric composition consisting essentially of chlorinatedbiphenyl and as a scavenger therefor about 0.05% to about 0.1% by weightof aminated-N-phosphoryl-o-aminophenyl, said chlorinated biphenylcontaining from 42% to 60% by weight of chlorine.

6. A dielectric composition consisting essentially of chlorinatedbiphenyl and as a scavenger therefor from 0.01% to 1% by weight ofaminated-N-phosphoryl-o-aminobiphenyl.

7. A dielectric composition consisting essentially of chlorinatedbiphenyl and as a'scavenger therefor about 0.1% by weight of aminated-N-phosphoryl-o-aminobiphenyl.

8. A liquid dielectric for transformers having substantially thefollowing composition.

8 Per cent by weight about Chlorinated biphenyl (60% Cl) 60Trichlorbenzene 40 Aminated-N-phosphoryl-o-aminobiphenyl 0.05-0.1

9. An arc quenching liquid dielectric medium having substantially thefollowing composition.

Per cent by Weight about Chlorinated biphenyl (60% c1) Trichlorbenzene50 Aminated-N-phosphoryl-o-aminobiphenyl 0.1

10. An arc quenching liquid dielectric medium having substantially'thefollowing composition.

Per cent by Weight about Chlorinated biphenyl C1) Trichlorbenzene 20Aminated-N-phosphoryl-o-aminobiphenyl 0.05

11. A capacitor impregnant having substantially the followingcomposition.

Per cent by weight about Chlorinated biphenyl (42%60% Cl) 0-100Chlorinated aromatic hydrocarbon other than chlorinated biphenyl -0Aminated-N-phosphoryl-o-aminobiphenyl 001-1 12. A capacitor impregnanthaving substantially the following composition.

Per cent by weight about Chlorinated biphenyl (42%-60% Cl) 75Chlorinated aromatic hydrocarbons other than chlorinated biphenyl 25Aminated-N-phosphoryl-o-aminobiphenyl 0.1

13. A capacitor impregnant having substantially the followingcomposition.

Per cent by weight about Chlorinated biphenyl (55% C1) 75Trichlorbenzene m 25 Aminated-N-phosphoryl-o-aminobipheny1 0.1

EDGAR E. HARDY.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

1. A COMPOSITION OF MATTER CONSISTING ESSENTIALLY OF A HALOGENATEDAROMATIC COMPOUND AND AS A SCAVENGER THEREFORAMINATED-N-PHOSPHORYLO-AMINOBIPHENYL, SAID SCAVENGER BEING EMPLOYED INAN AMOUNT SUFFICIENT TO RENDER IN HALOGEN DECOMPOSITION PRODUCTS OF SAIDHALOGENATED AROMATIC COMPOUND SUBSTANTIALLY INNOCUOUS.